Pressure cooker closure structure



Patented Dec. 11, 1951 UNITED STATES PATENT OFFICE PRESSURE COOKER CLSURE STRUCTURE Bjrn F. Andersson, Ulvsunda, Sweden Application October 29, 1947, Serial No. 782,802 In Sweden September 11, 1947 1 Claim. (Cl. ZBO- 46) My invention relates to cooking utensils for cooking under greater than atmospheric pressure, and refers especially to a fixing and packing arrangement for a cover, which can be hermetically applied to such a cooking apparatus.

One object of the invention is to procure a cooking apparatus of the type above mentioned with a circular opening. A further object of the invention is to procure a cooking apparatus, in which a removable packing may be inserted between the cover in its closed position and an edge flange formed on the cooking apparatus. Stili another object of the invention consists in the provision of an edge flange on the cooking apparatus and a similar edge flange on the cover, which edge flanges form tapered packing surfaces, in between which there is applied a packing.

In the accompanying drawing which shows embodiments of the invention by way of example,

Fig. 1 shows a side view of a cooking apparatus. partly in section,

Fig. 2 is a cross section through a packing ring,

Fig. 3 is a detailed section on a larger scale of the packing flanges provided on the cooking apparatus and its cover,

Fig. 4 is a detailed section on the same scale as Fig. 3 of the packing flanges provided on the cooking apparatus and its cover but in a modified embodiment, and

Fig. 5 is a section of part of a packing ring according to a modified embodiment.

A cooking apparatus l of the common round cross section is at its upper edge shaped into an annular tapered packing flange 2. Between said flange and a tapered edge portion 3 on a cover 4 appertaining to the cooking apparatus there is placed a resilient packing ring 5, suitably of synthetic caoutchouc or any similar material. The inner circumference of the flange 2 has a slightly greater diameter than the outer circumference of the flange 3, so that the cover can freely be introduced through the opening limited by the flange 2 and be applied resting on a shoulder 6 at the upper edge of the cookers wall. After having placed the cover in its closed position the packing ring 5 is located in its tightening position between the flanges 2 and 3.

The packing ring is shown in Fig. 2 in its released position. This ring is plane and has a rectangular cross section and is provided with a tongue 1 directed inwards and forming a linger grip for being used when removing the packing from its tightening position. As will be seen by Figs. 1 and 3 the shape of the packing in its 2 tightening position differs slightly from the plane shape owing to the conicity of the packing surfaces. As the ring tends to take back its plane shape a tightening effect is obtained though the distance between the flanges 2 and 3 may be somewhat greater than the thickness of the ring. At over pressure in the cooking apparatus the ring is compressed as will be seen by Fig. 3, and its tightening abilities grow with the over pres sure as well as the friction forces between the ring and the flanges.

In order to limit the over pressure during the cooking the cover is provided with a safety valve. This comprises a rubber washer 8 provided with a hole 9, which rubber washer by means of a removable bow l 0 is brought to bear on the edges of an opening H of the cover.

The principle of the arrangement above described resides in that the opening of the cooking apparatus may be reduced, upon the application of a cover inside the edge of the opening, with the aid of a packing, so that the cover cannot be removed from the cooking apparatus. Said principle may be carried into effect with the aid of a packing flange folded inwardly on the upper edge of' the cooking apparatus; in Figs. 1 and 3, said packing flange is designated by 2. Fig. 4 shows a modified construction. Here, a packing flange 20 is plane and constitutes the upper portion of a ring 2| of Ushaped cross section, the lower flange 22 of said ring being connected to an annular shoulder 23 adapted to receive a cover having a plane edge portion 24. Otherwise, the cover may be formed as shown in Fig. 1. The upper surfaces of the edge portion 24 and of the flange 22 are approximately on the same level, so that a iiexible annular packing 25 of a square cross section can be introduced conveniently into the U,shaped ring 2l, the packing being then compressed between the cover and the flange 20 at a pressure above atmospheric in the cooking apparatus. The opening limited by the flange 28 permits the introduction of the cover into the position of closure. At a pressure above atmospheric in the cooking apparatus, the packing 25 is subjected to a turning moment of the kind manifesting itself in the packing shown in Figs. 1-3. To counteract deformation of the packing, the latter 'is provided with cores '26 from a relatively hard material, such as metal. Such cores may be of an arbitrary cross-sectional configuration, provided the condition is fullled that the cores take up the substantial portion offthe pressure produced, and that the packing maintains its flexibility' throughout, so asto permit of being introduced into the tightening position. Fig. 5 shows a portion of a packing ring 21 provided with cores. Said cores consist of spaced cylindrical bodies 29 uniformly disposed along the circumference of the ring. 29V denotes a tongue corresponding to the tongue l in Fig. 1, which facilitates the removal of the ring from the cookingY apparatus.

I claim:

In a pressure cocker or the like, including a receptacle and a cover therefor, a pressure seal comprising an upper end portion integral with the top edge of said receptacle, said upper end portion being of greater diameter than the side wall of the receptacle and providing an upwardly facing shoulder at the top edge of said receptacle, an inwardly and upwardly extending frustoconical flange integral with the top edge of the portion of greater diameter, the under face of said frusto-conical iiange having a downwardly and inwardly facing sealing surface, an outwardly and downwardly extending frusto-conical peripheral ange on said cover, said peripheral flange having its greatest outside diameter less than the smallest inside diameter of the ange on the receptacle, whereby the cover is free to pass through the orice dened by said receptacle flange, said peripheral ange having an upwardiy and. outwardly facing sealing surface which is parallel to and spaced from the sealing surface of the receptacle ange when the cover is in closing position with the outermost edge of its ange resting upon the'shoulder at the top of the receptacle, and a exible and elastic packing ring of substantially square radial cross section loosely disposed between said parallel surfaces, said packing ring having a thickness somewhat less Ythan the distance between said surfaces and in non-assembled released condition having plane annular parallel faces and cylindrical inner and outer surfaces joining said annular parallel faces.

BJRN F. ANDERssON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,369,249 Kroupa Feb. 22, 1921 1,428,399 Schilling Sept. 5, 1922 1,878,677 Curtis Sept. 20, 1932 2,324,333 Stoddard July 1,3, 1943 2,379,053 Weingart June 26, 1945 FOREIGN PATENTS Number Country Date 216,555 Switzerland Dec. 16, 1941 261,480 i Germany June 23, 1913 817,534

France May 24, 1937 

